The instant invention describes a tailgate mounted drag reducing aerodynamic stabilizer or aerostabilizer wing for a pickup truck. This aerostabilizer wing is mounted on the pickup truck's tailgate so that it moves with the tailgate and as such is out of the way when the tailgate is opened for carrying cargo. It is disposed distal from the tailgate, over at least a majority of its span, so that, when the pickup truck is moving forward, it acts to: 1) place a downward aerodynamic generated force on the aft end of the cargo bed of the pickup truck and 2) reduce drag of the pickup truck since an aerodynamic pressure front that builds up on the forward side of the tailgate is at least partially bled off through an especially configured opening between the aerostabilizer wing and the tailgate. This is all done with a very attractive aerodynamically shaped unit that lends itself to low cost manufacture and that also offers high strength and easy installation.